The Broad Ripple Village Association (BRVA), founded in 1969, represents approximately 3,000 residents and 700 businesses in Broad Ripple, a designated Cultural District located within the North Midtown Economic Development District. As previously stated in our September 27th, 2012 letter to the U.S. Army Corps of Engineers, our organization is “eager to support a flood wall completion plan that can be certified in a timely manner and that ultimately offers relief from the expense of flood insurance and/or flood proofing.”

We continue to be in support of the alignment that provides completion and certification of the flood wall. The prior administration announced a decision in December 2015, prior to releasing the results of a long-awaited study to evaluate the Canal West Bank Alignment option. Now that the full study is available, we ask your administration to review the study results and to confirm the City’s position regarding the final alignment.

We recognize that a decision affects more than just our neighborhood and we hope the City selected alignment, to the best of its ability, maximizes the preservation of life and property and protects as many families and homes as possible in the impacted flood area. We do, however, proudly represent the individuals and businesses of Broad Ripple and our constituents remain in a precarious position without the completion and certification of the flood wall.

During your review, we ask your administration to carefully consider the protection of the City’s drinking water supply and, to the extent it can be preserved, Holcomb Gardens on the Butler University campus.

We kindly request an update regarding whether or not the City will accept the Ballard administration’s decision as it stands or if it plans to reevaluate it by February 15, 2016.

The BRVA supports the completion of the flood wall and an alignment that will ultimately be certified by FEMA, thereby relieving our constituents of the costly expense of flood insurance and/or flood proofing, broadening opportunities for development and, preserving life and property in Broad Ripple.

On behalf of the board of directors for the Broad Ripple Village Association (BRVA), I thank those who reached out to the organization to express their thoughts regarding the Ballard administration’s selection of the Westfield Blvd. Alignment and its decision to proceed to find funding to complete the construction of Phase 3B of the Indianapolis North Flood Damage Reduction Project.

In 2012 the BRVA recorded its position with the U.S. Army Corps of Engineers and City of Indianapolis as “withholding support” for the Corps recommended Westfield Blvd. Alignment due to “Concerns raised about the safety of Rocky Ripple residents, the gross clear-cutting of trees, the risk to the City of Indianapolis’ drinking water supply, and the walling off of neighborhoods.” During that time many issues were still under evaluation. Neighborhoods and environmental preservation organizations were examining options to preserve trees along the levee, as there seemed to be legal precedent in other areas of the country that trees could be saved. Groups were exploring the possibility of partial certification for the existing length of the flood wall, as well as, digesting the possibility of a sixth alternative alignment that, if feasible, could protect the City’s drinking water supply and lessen several southern neighborhoods’ concerns about being “walled off”.

The City and the Corps both confirmed that funding Phase 3B was not in hand and that they couldn’t speculate when funds may be found as funding for these sorts of projects are difficult to come by. Believing that the City and Corps should evaluate every possible option to protect and preserve neighborhoods, we, the BRVA, in consensus with other affected Midtown neighborhoods, asked the City to study this sixth alternative, which was coined the Canal West Bank Alignment. The city agreed to fund the study.

On December 9, 2015 the Ballard administration announced it would support the Corps recommendation to complete the Westfield Blvd. Alignment, citing study results that deemed the Canal West Bank Alignment infeasible. The study document was edited on December 18, released to the public on December 28, and the Ballard administration left office on December 31. The BRVA board discussed the announcement and study findings at its January 5, 2016 board meeting and determined a course of action.

As residents and business owners of the Village ourselves, we are your neighbors. We share your interests and your desires to make the Village a safe and prosperous neighborhood and Cultural District. Please find our letter to the Hogsett administration attached, calling for his attention to the flood wall issue and asking for his help in completing the flood wall.

The Indianapolis North Flood Damage Reduction Project (“project”) seeks to remove from the flood plain approximately 2,100 homes and businesses. Removing from the flood plain the approximately 4,000 people who likely live in these homes protects them from the very real and present threat of severe flooding with devastating consequence. Additionally, removing these homes and businesses from the flood plain protects these homes and businesses from the financial burden of annual premiums for flood insurance, which, for some are in the range of $8,000 – $10,000 per year. Millions of dollars a year literally leave the local economy due to flood insurance requirements.

The City of Indianapolis (“City”) recently released its common-sense decision to leverage federal funds and complete the project. The City’s decision enjoys widespread support throughout Indianapolis. The Warfleigh Neighborhood Association supports the City’s decision. Participating members of SaveWarfleigh, Inc. support the City’s decision. Approximately 900 signatories to a petition urging the City to expeditiously complete the project support the decision. These individuals reside throughout Indianapolis. Elected representatives at both the federal and local level support the City’s decision. Citizens Energy Group supports the City’s decision, the United States Army Corps of Engineers (“Corps”) supports the City’s decision, and the City’s Department of Public Works supports the City’s decision.

Unfortunately, the Butler-Tarkington Neighborhood fails to support the City’s decision and recently distributed for immediate release a call to once again delay the project.

I’ve had the opportunity to review and consider in detail the BTNA’s call for project delay (“BTNA alternative”). I conclude the BTNA’s alternative exhibits certain weaknesses and flaws that undermine its ability to serve as a credible alternative. The BTNA’s alternative also fails to share important facts and raises serious questions and concerns. I provide perceived weakness, flaws, questions and concerns below:

(1) Representativeness. The BTNA releases a public policy statement that affects the very lives and well-being of over 4,000 individuals in the flood plain. It is the BTNA’s responsibility as a good neighborhood steward to demonstrate their position is widely held, both throughout their own neighborhood and throughout Indianapolis. The BTNA must provide evidence that “thousands of residents vehemently oppose” project completion. The BTNA must provide evidence that those Butler-Tarkington residents who live or soon will be mapped into the flood plain support the BTNA’s recent alternative. The BTNA should indicate to what extent the Board sought community and neighborhood input when formulating its December 15, 2015 policy position, especially in light of recent developments.

(2) BTNA: The City’s decision “runs counter to the city’s understanding of community objection and previously stated objection (sic) the Westfield Boulevard alignment.”
The BTNA here seeks to communicate for the City when it indicates the City’s decision runs counter to the city’s understanding of community objection. The BTNA cannot presume to know what the City may or may not understand. Nor can the BTNA claim to understand what conclusions the City may have reached based on community input – though the City’s recent decision to complete the project provides strong indication of such.
(3) “The BTNA has long opposed this option (the Westfield Boulevard Alternative) because of the threat it creates for catastrophic damage to the Central Canal.”

Flood waters currently will inundate the Central Canal in case of a significant flood event. The BTNA’s call to delay the project does nothing to eliminate its perceived threat to the Central Canal. Additionally, the BTNA offers no other alternative to actually protect the canal – especially, troubling because its last most favored alternative, the Canal West Bank Alignment, again, proves infeasible.
(4) The Westfield Boulevard Alignment creates catastrophic damage to the Town of Rocky Ripple in a major flood event and effectively prevents Rocky Ripple from future flood protection.

(i) Completing the project provides no flood protection benefit to Rocky Ripple. Abandoning the project provides no flood protection to Rocky Ripple. Abandoning the project imposes considerable cost upon 4,000 flood plain residents. Simply, the BTNA’s proposed alternative imposes extreme hardship and cost upon many, and, at the same time, provides benefit to no one. This clearly is an unreasonable strategy and alternative.
(ii) I’ve attached a project diagram. Inspection of the map shows completing the currently proposed project phase will not impair the possibility of future Rocky Ripple protection. The most likely factor preventing Rocky Ripple protection at this time is the $50,0000,000 project cost compared to the $5,000,000 in project costs required to complete the current phase. The BTNA must provide strong evidence, technical evidence, to support its claim that completing the Westfield Boulevard segment of the project effectively prevents Rocky Ripple from future protection.

(iii) The BTNA’s most recently preferred alternative, the Canal West Bank Alignment, provided no flood protection for Rocky Ripple. Additionally, completing that alignment would have required demolishing at least six Rocky Ripple homes. It seems disingenuous for the BTNA Board to propose delaying the project now because it fails to provide Rocky Ripple protection, while at the same time, its own preferred alternative, the Canal West Bank Alignment, similarly provides no Rocky Ripple protection.

(5) The Westfield Boulevard Alignment creates a 6-foot flood wall that will be a blank canvas for graffiti and create a sight barrier to activities happening across the canal on the towpath.

(i) The Westfield Boulevard Alignment consists of a fixed flood wall segment, significantly less than 6-feet in height, and a removable segment that will be installed only in the event of a flood event. I’ve attached project renderings for proposed portions as well as completed portions. Please note the actually completed section of the project is not laden with graffiti. Please also drive along Riverview Drive, from approximately Kessler Boulevard to 64th street to see the extent to which the completed portion of the project has become a target for graffiti. I think many of you actually will concur this completed segment presents no aesthetic concerns.

(ii) The Westfield Boulevard Alternative in many places will replace invasive honey-suckle that has reached a height in excess of the fixed portion of the flood wall. Completing the project actually will increase the view plain relative to the BTNA’s proposed alternative.
(6) The Westfield Boulevard Alignment will run through historic Holcomb Gardens on the Butler University campus.

The Corps of Engineers identified Holcomb Gardens as a unique resource within the path of the Westfield Boulevard Alternative as early as April of 2009 and included it in their consultation under Section 106 of the National Historic Preservation Act with the Indiana State Historic Preservation Officer (IN SHPO) and other consulting parties. Based on the Westfield Boulevard Alternative design, only the eastern side of Holcomb Gardens would be affected if the Westfield Boulevard is selected as the proposed action. See Appendix E, Final Supplemental Environmental Impact Statement.

Again, based on my review, the BTNA’s current proposal to once again delay project completion exhibits certain weaknesses and flaws that undermine its ability to serve as a credible alternative. The BTNA’s alternative also fails to share important facts and raises serious questions and concerns. I counsel extreme caution when making public policy statements that affects the very lives and well-being of over 4,000 individuals.

I urge the BTNA to engage in a fact-based discussion and to freely share with all the facts upon which its policy pronouncements rest. I also urge the BTNA to drop its opposition to this project and, instead, to cooperate and collaborate with the City in order to develop an aesthetically pleasing final solution to a project that has languished for over 20 years. The project benefits are clear and incontrovertible.

The term “100-year flood” or living in the 100-flood plain, does not mean that the chance of a flood comes only every hundred years, but rather it means that statistically there is a 1 percent chance of a flood occurring in any given year. For any given “X-year flood”, divide 100 by X and that is the percent chance of a flood for that year.

Here is some great information regarding Flooding and 100-year floods
Read original article HERE

Floods: Recurrence intervals and 100-year floods (USGS)

Possibly you can remember when a really big rain, be it from a hurricane or a large frontal system, hit your town. If flood conditions occurred because of the rain then you might have heard the radio or TV weatherman say something like “This storm has resulted in a 100-year flood on Soandso River, which crested at a stage of 20 feet.” Obviously, this means that the river reached a peak stage (height) that happens only once every 100 years, right? A hydrologist would answer “Well, not exactly.” Hydrologists don’t like to hear a term like “100-year flood” because, scientifically, it is a misinterpretation of terminology that leads to a misconception of what a 100-year flood really is.

Instead of the term “100-year flood” a hydrologist would rather describe this extreme hydrologic event as a flood having a 100-year recurrence interval. What this means is described in detail below, but a short explanation is that, according to historical data about rainfall and stream stage, the probability of Soandso River reaching a stage of 20 feet is once in 100 years. In other words, a flood of that magnitude has a 1 percent chance of happening in any year.

What is a recurrence interval?

“100-year floods can happen 2 years in a row”

Statistical techniques, through a process called frequency analysis, are used to estimate the probability of the occurrence of a given precipitation event. The recurrence interval is based on the probability that the given event will be equalled or exceeded in any given year. For example, assume there is a 1 in 50 chance that 6.60 inches of rain will fall in a certain area in a 24-hour period during any given year. Thus, a rainfall total of 6.60 inches in a consecutive 24-hour period is said to have a 50-year recurrence interval. Likewise, using a frequency analysis (Interagency Advisory Committee on Water Data, 1982) there is a 1 in 100 chance that a streamflow of 15,000 cubic feet per second (ft3/s) will occur during any year at a certain streamflow-measurement site. Thus, a peak flow of 15,000 ft3/s at the site is said to have a 100-year recurrence interval. Rainfall recurrence intervals are based on both the magnitude and the duration of a rainfall event, whereas streamflow recurrence intervals are based solely on the magnitude of the annual peak flow.

Ten or more years of data are required to perform a frequency analysis for the determination of recurrence intervals. Of course, the more years of historical data the better—a hydrologist will have more confidence on an analysis of a river with 30 years of record than one based on 10 years of record.

Recurrence intervals for the annual peak streamflow at a given location change if there are significant changes in the flow patterns at that location, possibly caused by an impoundment or diversion of flow. The effects of development (conversion of land from forested or agricultural uses to commercial, residential, or industrial uses) on peak flows is generally much greater for low-recurrence interval floods than for high-recurrence interval floods, such as 25- 50- or 100-year floods. During these larger floods, the soil is saturated and does not have the capacity to absorb additional rainfall. Under these conditions, essentially all of the rain that falls, whether on paved surfaces or on saturated soil, runs off and becomes streamflow.

How can we have two “100-year floods” in less than two years?

This question points out the importance of proper terminology. The term “100-year flood” is used in an attempt to simplify the definition of a flood that statistically has a 1-percent chance of occurring in any given year. Likewise, the term “100-year storm” is used to define a rainfall event that statistically has this same 1-percent chance of occurring. In other words, over the course of 1 million years, these events would be expected to occur 10,000 times. But, just because it rained 10 inches in one day last year doesn’t mean it can’t rain 10 inches in one day again this year.

What is an Annual Exceedence Probability?

The USGS and other agencies often refer to the percent chance of occurrence as an Annual Exceedance Probability or AEP. An AEP is always a fraction of one. So a 0.2 AEP flood has a 20% chance of occurring in any given year, and this corresponds to a 5-year recurrence-interval flood. Recurrence-interval terminology tends to be more understandable for flood intensity comparisons. However, AEP terminology reminds the observer that a rare flood does not reduce the chances of another rare flood within a short time period.

Does a 100-year storm always cause a 100-year flood?

No. Several factors can independently influence the cause-and-effect relation between rainfall and streamflow.

Extent of rainfall in the watershed: When rainfall data are collected at a point within a stream basin, it is highly unlikely that this same amount of rainfall occurred uniformly throughout the entire basin. During intensely localized storms, rainfall amounts throughout the basin can differ greatly from the rainfall amount measured at the location of the rain gage. Some parts of the basin may even remain dry, supplying no additional runoff to the streamflow and lessening the impact of the storm.

Soil saturation before the storm: Existing conditions prior to the storm can influence the amount of stormwater runoff into the stream system. Dry soil allows greater infiltration of rainfall and reduces the amount of runoff entering the stream. Conversely, soil that is already wet from previous rains has a lower capacity for infiltration, allowing more runoff to enter the stream.

Relation between the size of the watershed and duration of the storm: Another factor to consider is the relation between the duration of the storm and the size of the stream basin in which the storm occurs. For example, a 100-year storm of 30-minutes duration in a 1-square-mile (mi2) basin will have a more significant effect on streamflow than the same storm in a 50-mi2 basin. Generally, streams with larger drainage areas require storms of longer duration for a significant increase in streamflow to occur. These and other factors determine whether or not a 100-year storm will produce a 100-year flood.

The 100-year flood level can change

Since the 100-year flood level is statistically computed using past, existing data, as more data comes in, the level of the 100-year flood will change (especially if a huge flood hits in the current year). As more data are collected, or when a river basin is altered in a way that affects the flow of water in the river, scientists re-evaluate the frequency of flooding. Dams and urban development are examples of some man-made changes in a basin that affect floods, as shown in the charts below.